Lowering blood pressure significantly reduced the risk of developing dementia among adults with hypertension in China compared to usual care.
A four-year, intensive blood pressure intervention was associated with a significant reduction in the risk of dementia development among adults with hypertension, compared to those who received usual care.1
The late-breaking research, presented at the American Heart Association (AHA) Scientific Sessions 2023 in Philadelphia, Pennsylvania, showed the intervention program in rural China significantly reduced systolic blood pressure by an average of 22 mmHg and the risk of all-cause dementia by 15% in people with hypertension.
“This is the first, large, randomized trial to demonstrate that lowering blood pressure is effective in reducing the risk of dementia in people with high blood pressure,” said Jiang He, MD, PhD, a professor of epidemiology and medicine and director of the Translational Science Institute at Tulane University, in a statement.1 “These findings emphasize the importance of widespread adoption of more intensive blood-pressure control to reduce the global burden of dementia.”
Per the AHA’s 2023 Statistical Update, nearly half of all adults in the United States have high blood pressure.2 According to the Aging, Demographics, and Memory Study, a supplemental study of the Health and Retirement Study, the estimated rate of dementia in US adults ≥65 years of age was 10.5% in 2012, with a rate of 7.3% in males and 12.9% in females.1
Without the presence of curative treatments, He noted the primary prevention of dementia through risk factor reduction is a priority in public health.
“Previous observational studies have found that individuals with untreated hypertension have a 42% increased risk of dementia compared with healthy adults, while individuals with treated hypertension have no significant increase in dementia risk compared with healthy adults,” He said.1
In this analysis, investigators assessed the effectiveness of lowering blood pressure on dementia risk in those with hypertension, across 326 villages in rural China. The trial, beginning in May 2018 and ending in March 2023, included approximately 34,000 adults aged ≥40 years with an untreated blood pressure of ≥140/90 mmHg or ≥130/80 mmHg for those at high risk for cardiovascular disease or those currently taking blood pressure medication, respectively.
At enrollment, the average age of study participants was 63 years old; 61% identified as women, and 39% identified as men. Investigators noted there were similar reductions in blood pressure and dementia risk among women and men. For analysis, He and colleagues assessed the effectiveness of lowering blood pressure on dementia risk among individuals with hypertension.
Half of the villages were randomly assigned to a village doctor-led intensive blood pressure intervention program and half of the villages were randomly assigned to usual care. Those in the usual care villages received their hypertension management from local village doctors or primary care physicians at township hospitals, as part of routine health service coverage in China.
Within the intervention group, trained village doctors initiated and adjusted antihypertensive medication, based on a treatment protocol, to achieve the goal of lowering systolic blood pressure to <130 mmHg and diastolic blood pressure to <80 mmHg, with supervision from primary care physicians.
The stepwise protocol included a treatment algorithm, medication selection, review of medication contraindications, and dose adjustment strategies. In addition, it provided discounted and free blood pressure medication to patients and health coaching on lifestyle modifications, home blood pressure measurement, and medication adherence.
At the end of the 4-year study period, certified neurologists who were blinded to randomization assignments conducted cognitive function assessments. The final diagnosis of all-cause dementia or cognitive impairment, no dementia was made by an expert adjudication panel, who were also blinded to intervention assignment. The classification of cognitive impairment, no dementia encompasses reduced functioning that does not meet the criteria for dementia but exceeds normal, age-related cognitive decline.
Upon analysis, those in the intervention group experienced significant improvement in blood pressure control and reduced dementia and cognitive impairment, no dementia, compared to those who received usual care. The data showed the average blood pressure in the intervention group at 48 months was 128/73 mmHg, compared to 148/81 mmHg in the usual care group.
On average, systolic blood pressure decreased by 22 mmHg and diastolic blood pressure decreased by 9 mmHg among those in the intervention group, compared to usual care. In addition, individuals in the intervention group had a 15% lower risk of dementia and a 16% lower risk of memory impairment. Regarding safety, serious adverse events, including hospitalization and all-cause death, were found to be less frequent in the intervention group.
He and colleagues indicated the limitation of the analysis included the lack of assessment of baseline cognitive function at the time of trial enrollment. They noted future research is needed to examine if lowering blood pressure will reduce dementia risk among adults with a high risk for dementia, without hypertension.